Mana Starved
by charlotteXOyates
Summary: In all honesty, Shirou wasn't quite sure how the two of them got into this situation. Archer was in need of mana and Shirou had apparently decided he was into selfcest. Neither of them were complaining. WARNING: GRAPHIC YAOI, EXPLICIT LANGUAGE, BOY X BOY, SMUT. If this is not your cup of tea, save yourself the time and just turn back now. Other than that, feedback is appreciated!


**Soooo yeah. This is a thing, I guess.**

 **If you don't like explicit sex and you're just going to flame; WHAT ARE YOU DOING HERE?! TURN BACK NOW! YOU'VE BEEN WARNED!**

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Archer's back arched against the headboard of the bed, letting a low, sinful groan escape his lips. Music to Shirou's ears. The servant had one eye shut in ecstasy as Shirou kneeled in between the man's legs, hands roaming his muscular, naked body and tongue teasing his nipple. He slithered one of his hands to the other nipple, playfully rubbing it in circular motions before pinching it aggressively. That really got a reaction out of Archer as his entire body convulsed.

"Shit, Shirou!" Hearing the older version of himself gasp his name like that sent Shirou's confidence levels through the roof. He traced his tongue up Archer's neck until he was biting and breathing on his ear.

"I guess you like it rough, huh?" Shirou taunted in a husky voice that was laced with pure lust. Archer's body twisted again as Shirou thumbed his nipples harder.

"You...uhn, you know what I like...it's the same as you..!" Archer retorted. He was still trying to keep his cocky character up despite the fact that his body was a hot mess beneath Shirou, and he _loved_ it. He loved that Archer was trying to act tough in this situation. He couldn't wait to screw the ego out of the sexy hunk's body. Just thinking about it made Shirou's blood pump harder as he nibbled on the nape of Archer's neck, leaving light marks.

"Then you better not complain about a single thing I do. Be a good servant boy and I'll feed your needy body all the mana it wants, you'll be so full of it you'll never need any more mana ever again." Shirou's hands were roaming lower now, appreciatively stroking Archer's abs. "But don't worry. Even if you don't need more mana, I'll make sure to cram more of mine into you time and time again just because I can." Archer shivered at the implications of Shirou's mana, looking into the boy's hungry eyes and cocky grin.

"...you're a real control freak, aren't you? Taking this master-servant thing a little far, if you ask me..." Shirou nibbled at the servant's bottom lip.

"Only because I know it turns me on, so it turns you on, too." Archer furrowed his brow but didn't argue, opening his mouth up and allowing Shirou to claim him. Shirou's face moved aggressively against Archer's, forcing the back of his head against the headboard. When he couldn't move his head any further back, he was forced to tilt his chin and give in to Shirou's aggressive kissing.

They made out furiously, passionately, desperately, their tongues locked in a dance of swords that both men found electric and incredible. Shirou's saliva was like an elixir to Archer; it lit his body on fire and took away his exhaustion and physical pain. He needed more of it. His mouth suctioned against Shirou's, taking in as much of his saliva as possible.

Meanwhile, Shirou found Archer's greedy mouth intoxicating in its own way. The servant _needed_ him so badly in the dirtiest ways possible and it was obvious with every action he made. His desire fueled Shirou's ego, his desperation fueled Shirou's addiction, and his obedience fueled Shirou's lust. He could hardly wait anymore.

Neither of them could bring themselves to stop making out for any longer than a split second, so Shirou began messily fumbling with their pants as Archer continued greedily inhaling Shirou's saliva.

 _Fuck, he's such a fucking_ slut _for my saliva...just imagining how desperate he'll be for my other bodily fluids is turning me on even more..._

Shirou was officially done playing around as his hands working on their pants went from impatient to frustrated. He regrettably pulled away from Archer to look down and discard both of them of their pants. Archer was panting heavily, face flushed from the passion of their make out session. His tongue was thickly coated in Shirou's saliva, hanging out at the front of his mouth slightly like a bitch in heat, desperate for more action.

Shirou licked his lips as their erections were freed. Now the real fun was about to begin. They leaned together, beginning to suck each other's face again as their hips closed the gap between them, and they squished their muscular bodies against each other.

In all honesty, Shirou wasn't quite sure how the two of them got into this situation. Archer had been exhausted and injured, Rin wasn't around, and Shirou had apparently decided he was into selfcest. Then again, he could always give the excuse that he was doing this purely to supply Archer with the mana he needed, but they both knew that was just an excuse. Neither of them complained.

"Ha...fuck, you're so fucking hot!" Shirou groaned as their cocks rubbed together as hard as they could, both men lustfully pressing their hips harder against each other, desperate for the delicious friction it caused. Their tongues danced as wildly as their hips, merging as one and milking the situation of all the pleasure they could get. Archer could feel their heads, heavy with precum, aggressively ramming into each other. He let out a moan and pulled away from Shirou, getting on all fours.

"Can't waste...a single drop." Archer explained as he crawled forward, his tongue trailing its way up the shaft of Shirou's huge cock and licking up his dripping precum. The servant's eyes shut in bliss as the precum lit his body on fire.

Shirou groaned, sticking his hips out and putting his arms behind his head, showing off his armpits as he let Archer do what he wanted.

"Don't worry, I've got plenty of _mana_ stored up in here." Shirou licked his lips, moving his hips forward a bit to slap Archer in the face with his balls. The sac of orbs was impressively large and heavy, promising a very large load.

Archer began sucking on Shirou's sweaty balls, his body desperate for their contents. Shirou grinned at Archer's displays of submissiveness. He rubbed his cock all over his face, worshipping it.

Shirou decided to kick it up a notch. He grabbed a hold of Archer's hair before tugging him down on his cock. Archer's eyes widened a bit before relaxing and going along with it, moving his head further down onto the abnormally large teenage cock. Shirou groaned in intense lust and pleasure, spreading his knees further apart and inserting more of his thick man meat down Archer's tight throat.

"Fuck yeah, Archer...if you want my boy juice you're gonna have to work for it..." Archer shut his eyes, focusing on the cock in his mouth. His head went all the way down on it until Shirou's massive balls were chafing his chin, sucking with vigor. Shirou moaned in response, leaning his head back a bit and bucking his hips forward. He wasn't sure how sexually experienced he was in the future, but if Archer's tongue action was anything to go by, he must be _pretty_ experienced.

Shirou began to rock his hips a bit as Archer's tongue massaged his cock in all the right ways. The head of his cock was being squeezed by Archer's throat, leaking raindrops of his addictive, delicious precum straight into Archer's body. The more of Shirou's fluids that Archer drank, the more desperate his sucking became, until eventually Shirou couldn't stand it. He went from rocking his hips to thrusting them, ramming his fat cock in and out of Archer's throat with a fistful of white hair in his fingers.

"Fuck, you really want my cum that badly, huh...FUCK Archer!" Shirou screamed. He unraveled his knees and stood up, his legs bent slightly as he put both hands in Archer's hair. He then began to ruthlessly face fuck his future self, loving how Archer's tongue would reach up to intercept as much of his delicious cock as it could as it passed through the roof of his mouth and stabbed his throat. He rolled his hips into Archer's face, letting the scent of his loaded balls rub off onto Archer possessively.

The servant loved every minute of being face fucked by his teenage counterpart, drinking in his intoxicating youthful sex aroma. Shirou's hips eventually came to a stop, and he pulled his dick out of Archer's mouth, sitting back down on the bed and leaning back a bit.

Meanwhile, Archer's sides were heaving in excitement. He grabbed a hold of Shirou's dick which was now covered in Archer's saliva.

"Damn...I don't remember being this big at this age. Nor do I remember being that good at fucking someone's face." Shirou grabbed Archer's hand and began to move it up and down his cock, a smirk on his face.

"And if I'm that good at fucking face, think about how good I'll be at fucking your ass." Archer groaned as he imagined it. His body helplessly sprawled out under a teenage version of himself who wasn't even legal yet, his backside being torn to shreds by the young boy's eager cock and endless sex drive as he fed Archer all the mana he could ever want and more. The selfcest fantasy made him shiver, and in the next moment he had turned around on his hands and knees.

"Do it, Shirou." Neither of them were able to hold themselves back at this point as Shirou bent down, spreading Archer's ass cheeks and revealing his delectable pink hole.

"Ah!" Archer gasped out as Shirou's tongue poked his entrance. He traced it in a circular motion before plunging his face against Archer, eating and sucking against his ass. Archer let out a low moan, raising his rump against Shirou's face. The teen's tongue dug in as far as it could go, wetting Archer's walls. Feeling how tightly his ass was contracting around his tongue made Shirou's cock throb in impatience. He somehow managed to keep himself under control for a bit longer, wanting to taste Archer a little more.

Shirou pulled his face back a little bit before thrusting his tongue through the hole, tongue fucking Archer's ass. That got some more lewd noises out of the servant. He arched his back, pushing his ass back against Shirou some more.

"Your cock...give it to me. I need your mana." Shirou pulled away and crouched behind Archer, rubbing his cock against his tan ass teasingly.

"You do now, do you." He leaned his stomach against Archer's back, breathing hotly against Archer's ear. "How badly do you need it." Archer narrowed his eyes frustratedly back at Shirou, but the stupid grin on his face told him he wouldn't get it unless he begged. Archer cursed his sadism before speaking.

"I need it so badly...if I could wish on the grail I'd wish for you to be able to fuck me nonstop, I'd wish for you to never get tired so you could always have more sperm, more _mana,_ to feed my body. I need your cock to live, Shirou..." Shirou licked the nape of Archer's neck affectionately.

"Really? So you'd wish to get fucked by a teenage version of yourself? Just how naughty are you, Archer?" Archer rolled his eyes.

"Be quiet. Aren't you the one fucking a dead, future version of yourself?" Shirou chuckled as he pulled his body back.

"Fair enough. Oh, and about that wish of yours, Archer...about wanting me to never get tired so I can fuck you nonstop, wanting me to have a pair that never gets empty..." Shirou pressed his cock against Archer's gaping, wet hole, making him hold his breath in anticipation. Shirou smirked. "I've already got that all going for me, so you don't need to wish it. Because I'm gonna fuck you nonstop, and that's reality. Just don't regret wishing for it!" With that, Shirou slammed his hips forward, connecting him and Archer.

Archer's eyes flew wide open, and he threw his head back in a loud howl of pleasure. Shirou was merciless and sadistic as all hell, shoving his entire cock inside of him in one go. His prized balls caressed Archer's backside as he let his cock rest in the incredibly tight warmth, relishing the pleasure as his cock was squeezed.

"Fuck...oh fuck...I didn't know...I didn't know it felt this good..." Shirou groaned, bucking his hips into Archer. "If I knew it felt this good I would've been fucking Issei since junior high..." Archer was in a somewhat similar state, his mind boggled as incomprehensible noises of pure pleasure escaped his lips.

"I've taken many cocks, but getting fucked by myself...this is different...incredible...or maybe it's just because I need your mana so badly right now..." Shirou managed to grin through his pleasure-ridden face.

"Is that your way of telling me to fuck you already?" Archer glared back at him as best he could, breathing heavily from having his own cock up his ass.

"What, do you need more of an invitation that that?"

"Well, when you put it that way-"

"FUCK ME SHIROU." Shirou chuckled before pulling his hips back slowly, relishing the feeling of Archer's tight ass clamping down and trying to keep his cock inside.

"You say you've taken many cocks, but how are you still so tight..." Archer groaned as he felt Shirou's cock leaving him, creating an emptiness as it went.

"It's a talent we share...now, shut up, and fuck me." Shirou was right behind him. He slammed his hips forward as best he could through the tight walls, brute forcing his way through if he had to. He and Archer both groaned in pleasure as his cock was once more buried in the heat that felt like it was made to take himself up the ass.

"Waiting so long to finally lose my virginity to myself...so worth it..." Shirou groaned. He pulled his cock back before slamming it forward once again, moving Archer's entire body forward a bit as he did so from how hard he thrust. Archer moaned in pleasure.

"What's wrong..? I thought you were gonna fuck me nonstop? I guess those were just the cocky words of a bratty teenage virgin...guess I'll have to find a mana supplier elsewhere." Archer taunted, desperate to coax Shirou into going wild. It worked. Shirou's face became dark and merciless as he mounted Archer doggy style.

"Is that so. Let me teach you something," Shirou pulled his hips back. "You will never get mana anywhere other than from MY HUGE COCK!" Shirou roared at the end of his sentence, ramming his cock forward into Archer and holding his body in place so he wouldn't go flying from the force behind the thrust. Archer cried out in pleasure, but before he could say anything, Shirou had thrust a second time. And a third time. Pretty soon, there was no room for Archer to speak as he was ruthlessly fucked by himself. So, so ruthlessly. And Shirou was getting off on it like a sex demon.

"How's that, huh? You like that? Who's the bratty virgin now? I'd like to see you _try_ to get mana from someone else after this because when I'm done with you your ass will be torn open so wide I could fit my head inside. Nobody will even want to fuck your used ass. All it'll be good for is for pleasing my big dick." Archer's moans got louder and louder from Shirou's unbelievably hot promises until he was screaming now, every noise he made a desperate plea for Shirou to keep fucking him the way he was.

Shirou had his arms fastened tight around Archer's body, keeping them stationary as his hips brutally mashed against Archer's. He could practically feel his cock bending and reshaping Archer's insides with each thrust. However, no matter how hard he thrust, no matter how badly he destroyed Archer's hole, it only seemed to get tighter and tighter the harder he thrust, as though rewarding and coaxing him to just fuck his new bitch harder. And Shirou did just that.

His hands snaked their way around Archer's cock as he fucked him, increasing the amount of pleasure the servant was feeling. Shirou reached forward and put two fingers in Archer's mouth, hooking them inside his cheek while the rest of his hand cupped Archer's chin. Both men were cursing and shouting as they lost themselves in each other's bodies.

Shirou left love bites all over the back of Archer's neck and his shoulders, wanting to completely ravish and control him. Archer wasn't complaining as he gave himself to Shirou, moaning in pure lust as he ground his hips back against the boy's huge cock as hard as he could. The feeling of Shirou's dick spearing him so fast and so hard sent shockwaves throughout his body. He could only imagine what it'd be like to experience that pleasure while simultaneously having his body absorb Shirou's mana through sperm.

Shirou slammed his hips forward particularly hard, driving his cock straight into Archer's prostate. His eyes widened and he let out a less than manly shout.

"Fuck! Surely this isn't your limit?" Shirou's eyes flashed at Archer's challenge. He got up and flipped Archer onto his back, lifting his legs up and spreading them on either side of Shirou's body. He was still kneeling as he buried his cock inside of the servant even harder, ramming straight into his sensitive prostate.

"Fuck! Yes, like that!" Archer gasped, gripping onto the bed for dear life as Shirou began fucking his raw ass, shoving the head of his cock straight into his prostate with each movement of his hips. Archer's body spasmed with each hit. His eyes were screwed shut tightly as Shirou brutally dominated him, the teen's huge balls filling the room with the sound of skin harshly slapping skin.

Archer risked looking up at Shirou, and the primal, sex-driven look in his eyes sent Archer overboard. He could barely recognize the teen imposing his desires onto his body as himself. He couldn't remember being this incredible and sexy, but he was glad Shirou was as he gave in to the feeling of Shirou's dick destroying him.

With a scream of pleasure, Archer came all over his abs, his large cock spewing out loads of his sperm. Feeling Shirou continuing to slam into his prostate didn't help in the slightest, and his screams only got more intense at the feeling of his prostate consistently being pounded by the teen alongside the feeling of his orgasm reaching its peak. Just knowing that this younger version of himself was holding in his cum better than him was such a turn on. It'd been a while since he let himself cede superiority like this. He knew that Shirou was fighting his climax as much as possible so that he could explode Archer's ass with as much cum as possible. That thought made Archer squeeze his ass tighter.

Shirou's hips began moving more desperately, fucking Archer into the bed as his balls tightened. He stared down at Archer's body, covered in his own cum, as he himself prepared to let loose.

"Archer...fuck, this is it...what you've been waiting for...!" Archer groaned in pleasure, lifting his hips to buck his ass against Shirou's cock.

"Fuck me, Shirou! Fuck me like you're trying to impregnate me!" That line got to Shirou as he finally lost all control. He slammed his hips forward as hard as he could, slamming his cock right into Archer's prostate and grinding it in as he erupted. Both of them screamed curses of pure lust and pleasure as Archer could feel his body being flooded with the largest load he'd ever taken.

Shirou grabbed Archer's hips more tightly and began moving his hips again, fucking Archer and riding out his massive orgasm. His cock shot load after load of his fertile teenage sperm deep inside of Archer. The servant's body graciously accepted his seed, drinking it in and absorbing his mana into his circuits.

"Oh, Shirou!" Archer gasped, eyes widening as he felt Shirou's sperm entering his system and lighting his body on fire. It felt like he was being brought back from the dead. Archer writhed in pleasured agony, the feeling of Shirou's sperm feeding his body enough to make him cum all over his face. "Shirou! Give me more! More mana!" Shirou took one look at Archer's begging face, globs of his own sperm covering himself and tongue hanging out in submissive plea, and that was it. He shot another load.

"Fuck! Fuck, Archer!" Shirou screamed out his name as he slammed his hips forward and let his second orgasm take over. His first one hadn't even finished yet, so now even larger amounts of his rejuvenating sperm was firing out of his dick and into Archer's suctioning asshole.

"Cum in me Shirou! Fuck!" Archer had all of his muscles flexed as his body desperately took in Shirou's magus sperm, revitalizing Archer's strength...and lust. The entire process was unbelievably pleasurable. So much so that it immediately caused Archer to cum again. For some reason, being fed mana from Shirou's sperm was more pleasurable than anything Archer had ever experienced, like Shirou's essence made his body especially sensitive. Perhaps because he was basically feeding himself mana from his own cock.

"M-more...Shirou," Archer gasped, grabbing onto Shirou's arm. "More mana, Shirou." Shirou obliged, letting out a battle roar as he began fucking Archer. There was no grace to his movements, no structure. He was just destroying Archer's cum-filled ass, using the tightness to satisfy himself until finally his seemingly bottomless balls tightened again. Both men screamed as Shirou fucked Archer while riding out his third orgasm of the day, his load just as thick and just as plentiful as the first one. Archer's eyes were ready to roll back into his head as he wrapped his legs around Shirou's back, getting his sperm as far in as he could go. His body continued to hungrily take in Shirou's seed as his ass milked Shirou's orgasm for everything it was worth.

The loads began dying down, and Archer's eyes widened.

"Shirou...!" He squeezed his ass on the boy's cock. "More mana! Feed my body more of your addictive mana, Shirou!" Shirou grunted, laying down beside Archer and changing position. He then wrapped his arms around Archer's chest and began to fuck the taller servant sideways, legs around Archer's hips.

"Oh!" Archer screamed out in pleasure at the change as Shirou fucked him just as ruthlessly as ever.

"Geez, even I couldn't have predicted what a fucking _slut_ you are! You're so greedy for my cock juice, huh?!" Archer groaned in response, rolling his hips backwards into Shirou's thrusts.

"You spoil me...your balls...have no end..." Shirou began fucking Archer more aggressively.

"That's right, and a good thing, too, or else you'd never have enough. I'm the only one who can satisfy you, you got that?" Archer's eyes flew wide open and he screamed in agreement as he came all over himself for again. Shirou smirked.

"Good. And if you ever forget...I'll do _this_!" Shirou growled, burying himself balls deep into Archer as he came again. Archer's body strained as he cried out, unable to ever get enough of Shirou's cum. He turned his head and the two of them kissed. It was sloppy and full of lust as their tongues slobbered all over the inside of each other's mouth. Archer moaned into the kiss as Shirou continued to pump mana into Archer's body from his cock. When their heads parted, thick lines of saliva connected their tongues together, and they were both panting.

"More, Shirou. More mana. I need it." Archer begged, his ass still flaring and squeezing Shirou's cock. Shirou pressed his balls against Archer's ass, signifying he had plenty more mana to give.

"You fucking slut." He sat up, bringing Archer on top of him. Archer immediately went down, impaling his body on Shirou's cock and riding him. Shirou groaned as Archer's muscular ass contracted around his cock. He began moving up and down as fast as he could, and they began making out again, messy as ever while Archer rode him.

"Fuck! With your skills I'd think you should be the rider class!" Shirou groaned. Archer held onto Shirou's body as he rammed himself onto the cock harder.

"Cum in me!" He practically ordered. Shirou screwed his eyes shut as he did just that, his balls doing god's work as they slammed against Archer's ass and catapulted their sperm out of Shirou's cock like a hose. They both screamed, neither of them moving this time as they just let Shirou flood Archer's body with his essence. Archer felt himself slump against the shorter boy, both of them panting. They made out briefly again before pulling away.

"Fuck, I think I love giving you mana." Archer ground his ass against Shirou's cock, which was as hard as ever.

"You can always give me more."

"You've already been begging like a slut," Shirou flipped Archer onto his back again. "Don't go thinking we're anywhere _near_ done yet." He slammed his cock into Archer's body, eager to feed the greedy slut all the mana in the world. They fucked and fucked for hours nonstop, and Shirou must've came a thousand times that night.

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